Role of hepatitis E virus antigen in confirming active viral replication in patients with acute viral hepatitis E infection.

BACKGROUND: Demonstration of active viral replication is important in serologically confirmed cases of hepatitis E virus (HEV) infection to assess prognosis. Detection of HEV RNA by reverse transcriptase polymerase chain reaction (rtPCR) is the gold standard for demonstration of active viremia. OBJECTIVES: The present study was designed to compare the diagnostic utility of HEV antigen (Ag) with HEV IgM and HEV rtPCR in detecting the active viral replication. STUDY DESIGN: Blood samples from 156 probable cases of acute viral hepatitis (AVH) were collected. Screening for hepatitis B surface antigen (HBsAg), antibody to hepatitis C virus (anti HCV), IgM antibody to hepatitis A virus (HAV IgM) was done on the Architect platform (Abbott Laboratories, IL, USA). HEV IgM ELISA (Wantai Biological, Beijing, China), HEV-Ag ELISA (Wantai Biological, Beijing, China) and HEV rtPCR were done on all the samples. RESULTS: Out of 156 AVH cases in 56 (35.8%) a diagnosis of HEV was confirmed. Positivity being; anti-HEV IgM 44/56, HEV RNA 20/56, and HEV antigen 17/56 in established cases. Male to female ratio was 3:1. The median age was 40 (range 14-71) years. HEV Ag showed a good concordance with HEV RNA (k=0.635, p<0.001). However HEV IgM did not show any concordance with HEV RNA (k=0.14). CONCLUSION: HEV antigen assay can be used as an additional diagnostic marker to confirm active viral replication in serologically positive samples.